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Achieve Peak Gas Engine Performance

The gas engine will always have a place on the American farm. Whether it’s found on a seed tender, small generator, pump, UTV, or the family lawnmower, it will need to have a method to atomize the fuel and to mix it with air. In other words, they all use a carburetor.
Carbs, at times, are feared by their owners, who perceive them to be too complicated to adjust.

Though a carburetor has many fuel and air pathways known as circuits, the foundation of its operation is the float circuit. This consists of the bowl, float, and inlet needle valve/seat.

Acts as a reservoir
The float bowl acts as a reservoir that feeds all of the fuel circuits. Thus, it has great influence on how the rest of the carburetor operates and, in turn, how the engine runs.

The float setting determines the fuel level in the bowl. Whenever a carburetor is serviced or taken apart, the float needs to be checked and the adjustment(s) confirmed.

If the fuel level in the bowl is too high, the engine can either flood or be excessively rich right off idle. To confirm this, gain access to the carburetor and look down its throat with the engine running at the speed/load the problem occurs. If you see raw fuel being dumped, the float level is the first place to look.

If the engine runs fine but lacks power under load, then it is possible that the fuel level is too low and the bowl is running out of gas and leaning the mixture. It’s possible for an engine to run fine at idle and light load, but when it is put to the task, it falls off greatly in power. 

Since the fuel level in the bowl is intrinsically linked to the float adjustment (low float height equals low fuel level and vice versa), it is a key setting that should never be overlooked.

Float differences
If the float is suspended from the air horn, it will have both a height setting (with the air horn inverted) and a drop adjustment (air horn upright).

When the float is moored in the fuel bowl, it will have only a height setting. 

It is paramount that you follow the manufacturer’s procedure for setting the float and its specification, which is usually a fraction of an inch.

Keep in mind where you are measuring from. For example, if the float is in the bowl and you are required to measure from the casting down, then the greater the value on the ruler, the lower the float height (it is farther from the top of the bowl). Also, make sure you bend the tang or float in the proper place for adjustment, especially with a height and drop setting.

If you only renew the gaskets in a carburetor and never check the float setting, you are cheating yourself out of the power and performance that engine has to offer.

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